Field of the Invention
The present invention relates to a pressure tank.
Discussion of the Background
The high pressure tank is widely used as a container for containing fluid such as gas, liquid, and the like. For example, the high pressure tank is mounted on fuel cell vehicle for containing hydrogen gas in order to supply to fuel battery system.
This kind of high pressure tank has a liner configuring an outer surface covered with a reinforcing layer made of fiber reinforced plastic and a resin hollow body. A hollow tubular portion is formed and projected on the liner. A base on which a supply/discharge hole is formed for supplying/discharging fluid to the inside of the liner is installed to the tubular portion. A valve is provided on the supply/discharge hole. The supply/discharge hole is opened and closed by operating the valve.
It is common that the high pressure tank seals between the liner and the base with a seal member. For example, it is mentioned in Japanese Laid-Open Patent Publication No. 2015-31307 that according to the configuration that the tubular portion is inserted into the base, a seal member attached to an outer peripheral surface of the base can seal between the outer peripheral surface and an inner peripheral surface of the tubular portion. However, in the configuration, the internal pressure of fluid may expand the tubular portion to the separating direction from the seal member. Moreover, it is supposed that the inner peripheral surface of the tubular portion causes shrinkage deformation by creep due to the fact that the liner is made of resin material. If such a situation happens, the distance (seal gap) between the inner peripheral surface of the tubular portion and the outer peripheral surface of the base is increased, which makes difficult to gain a sufficient sealability.
For example, as mentioned in Japanese Laid-Open Patent Publication No. 2013-137092, on the contrary to the above-mentioned configuration, the other is a possible configuration that the tubular portion is arranged inside the supply/discharge hole of the base, the seal member is interposed between the outer surface of the tubular portion and the inner surface of the supply/discharge hole. In the case, the seal member is attached to the inner peripheral surface of the base, and simultaneously, the internal pressure is applied to the direction that the tubular portion is pressed to the seal member side. Accordingly, the tubular portion presses and abuts on the base and the so-called self-seal structure is formed, which can maintain a seal gap approximately constant and can favorably seal the space between the tubular portion and the base.
Moreover, according to the configuration, the pressure of fluid is applied from the tip surface side to the tubular portion, if the strength of the tubular portion is insufficient, the tubular portion is easily separated from the base. Moreover, if the shrinkage deformation of the tubular portion is generated due to temperature drop, creep, and the like, the seal gap is increased, finally which leads to the degradation in sealability. In order to prevent these, the liner mentioned in Japanese Laid-Open Patent Publication No. 2013-137092 enhances the strength of the tubular portion due to the fact that the metal reinforcement is buried inside the tip surface of the tubular portion.